JP6554005B2 - Soil sample preparation equipment - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a soil sample preparation apparatus for preparing a soil sample used in a compounding test of a cement-based solidifying material used for ground improvement.

  The soil sample used for the blending test of the cement-based solidifying material used for ground improvement is, for example, as described in Patent Document 1, JCAS L-01-2006 “Improved body by cement-based solidifying material” The test specimen is prepared according to the definition of “Strength test method”. In preparation of this test body, in principle, a soil sample which has passed through a 10 mm sieve is used. Generally, this soil sample preparation operation is performed manually while removing foreign matter and the like.

JP 2014-218860 A JP 2010-99918 A

  However, some soil samples have high viscosity, and depending on the kind of the soil sample, it is necessary to press the soil sample through the sieve and pass it, and it takes a considerable time to prepare the soil sample. In addition, since this preparation work is done manually, it is safe to injure hands with glass pieces or shells contained in the soil sample, and infecting bacteria contained in the soil sample. There is a problem on hygiene such as there is a risk of Moreover, since the opening of the sieve mesh occurs due to repeated use, it is necessary to replace the sieve once every several months in order to ensure the accuracy of the blending test.

  By the way, although it is not an apparatus for preparing a soil sample, as described in Patent Document 2, an extrusion molding apparatus for extruding and molding a viscous material such as clay is known. Even if it is intended to apply such a viscous material extrusion apparatus to the preparation of a soil sample, the soil sample contains foreign matter, and the viscous material extrusion apparatus is immediately applied as a soil sample preparation apparatus. It is not possible.

  The present invention has been made in view of such circumstances, and can prepare a soil sample in a short time, can maintain safety and hygiene, and is excellent in durability. An object is to provide an apparatus.

  The soil sample preparation device of the present invention includes a cylindrical sleeve, a steel base bottom plate attached to the bottom side opening of the sleeve, and can be inserted into the sleeve and pressed in the axial direction of the sleeve. The base bottom plate is provided with a plurality of circular sieves each having a diameter of 10 mm or a square of 10 mm × 10 mm, and the lower portion of the base bottom plate is provided with the inside of the sleeve. The receiving part which collect | recovers the soil sample prepared by pushing the soil sample thrown in to the said mesh is provided.

Insert a soil sample into the sleeve, sandwich it between the base bottom plate and the piston body, and pass through the sieve of the base bottom plate, so that it passes through a 10 mm diameter or 10 mm x 10 mm square sieve. Soil samples with possible particle sizes can be produced. In addition, since the base bottom plate with sieves is made of high-stiffness steel material, the soil is removed from the sieves with a higher pressing force than when the soil sample is manually pressed against the sieves. The sample can be extruded, and the preparation of the soil sample can be performed in a short time. Furthermore, by using the steel base bottom plate, it is possible to prevent the opening of the sieve screen, but it is also possible to replace only the base bottom plate, thereby ensuring the accuracy of the soil sample mixing test. In addition, since the sleeve and the base bottom plate are separately formed, cleaning can be easily performed.
Since the soil sample preparation apparatus configured as described above can automate the preparation of the soil sample, the opportunity for the operator to directly touch the soil sample is reduced, and both safety and hygiene are achieved. It can be maintained.

In the soil sample preparation device of the present invention, it is preferable that a vibration means for vibrating the piston body in the axial direction of the sleeve is provided.
When preparing a soil sample from a soil sample with relatively low viscosity such as sandy soil or black dust, if it is pressed as it is, it will be compressed into a block between the base bottom plate and the piston body, causing clogging of the sieve It is easy to do. Therefore, by pressing the soil sample with the piston body and applying micro-vibration, the soil sample can be smoothly passed through the sieve to prepare the soil sample.

In the soil sample preparation device of the present invention, when the pressure load of the piston body is 10 kN or more and 100 kN or less, the total area of the opening area of the sieve screen formed on the base bottom plate with respect to the opening area A of the sleeve The opening ratio (B / A) of B is preferably 0.20 or more and 0.70 or less.
When the opening ratio (B / A) is 0.20 or less, the pressing load of the piston body is insufficient, and it becomes difficult to extrude the soil sample from the sieve and prepare it. On the other hand, when the opening ratio (B / A) exceeds 0.70, the intervals between the sieves formed on the base bottom plate are close, and the strength of the base bottom plate itself is reduced. It makes it difficult to make accurate preparations.

In the soil sample preparation device of the present invention, it is preferable that an R-chamfer with a radius of 1 mm or more and 5 mm or less is formed at the opening on the sleeve side of the sieve.
By forming an R chamfer in the above range in the opening on the sleeve side of the sieve, the soil sample can be smoothly flowed from the inside of the sleeve to the inside of the sieve, and the preparation time can be shortened, Cleaning time can be shortened.

  The soil sample preparation device of the present invention includes a cylindrical guide member provided to be engageable with an outer peripheral portion of the piston body, a connection position where the guide member is connected to an upper portion of the sleeve, and an upper portion of the sleeve. Lifting and lowering means for supporting the lifting and lowering movement away from the retracted position, and locking means for allowing the piston body to be inserted into the sleeve in a state where the guide member is disposed at the coupling position. Good.

  Since a guide member that can be engaged with the outer peripheral portion of the piston body is provided and the piston member and the sleeve are communicated with each other by this guide member, the movement of the piston body into the sleeve is guided by the guide member. The piston body can be smoothly inserted into the inside of the sleeve to press the soil sample. Further, in the state where the guide member is disposed at the coupling position with the sleeve, the sleeve is kept pressed by the guide member, so that the sleeve and the base bottom plate are prevented from being lifted. In the state where the guide member is arranged at the coupling position with the sleeve, the piston body is provided only in a state where the guide member, the sleeve and the base bottom plate are held at predetermined positions by providing a locking means that enables pressing by the piston body. Can be smoothly inserted from the guide member into the inside of the sleeve, and the preparation operation can be performed safely.

In the soil sample preparation device of the present invention, the lower surface of the piston body may be provided to maintain a distance of 20 mm or more between the lower surface of the piston body and the upper surface of the base bottom plate.
By ensuring a space of 20 mm or more between the lower surface of the piston body and the upper surface of the base bottom plate, contact between the piston body and the base bottom plate is avoided, and foreign matter is caught between the piston body and the base bottom plate. It is possible to prevent damage to the base bottom plate and the piston due to the above.

  According to the soil sample preparation device of the present invention, preparation of soil samples can be performed in a short time, and safety and hygiene can be maintained. Moreover, since the soil sample preparation apparatus of this invention is excellent in durability, preparation operation can be performed over a long period repeatedly.

It is a front view showing an embodiment of a soil sample preparation device concerning the present invention. It is principal part sectional drawing explaining the relationship of the piston body and guide member which partially broken and showed the soil sample preparation apparatus shown in FIG. It is principal part sectional drawing explaining the raising / lowering movement of the piston body which partially broken and showed the soil sample preparation apparatus shown in FIG. It is arrow sectional drawing in alignment with XX of FIG. It is principal part sectional drawing explaining the modification of the sieve of a base bottom plate.

Hereinafter, an embodiment of a soil sample preparation device according to the present invention will be described.
As shown in FIGS. 1 to 3, the soil sample preparation device 100 of the present embodiment includes a cylindrical sleeve 1, a base bottom plate 2 attached to the bottom side opening of the sleeve 1, and the sleeve 1 and the base bottom plate 2. , A piston body 4 that can be inserted into the sleeve 1 and can be pressed in the axial direction of the sleeve 1, and an outer peripheral portion of the piston body 4. A cylindrical guide member 5 and a receiver 6 for collecting the prepared soil sample are provided. The soil sample preparation device 100 includes an operation unit 7 provided with a plurality of switches and the like for performing operations of moving the piston body 4 and moving the guide member 5 up and down.

The sleeve 1 is formed in a cylindrical shape along the vertical direction, as shown in FIGS. 2 and 3, and is mounted on the gantry 3 via the base bottom plate 2.
The base bottom plate 2 is provided in the shape of a steel disc, and as shown in FIGS. 2 and 3, a recess 21 is formed on the inner circumferential side of the disc to engage with the outer periphery of the lower end of the sleeve 1 On the side, a flange portion 22 mounted on the gantry 3 is provided. As shown in FIGS. 2 to 4, the bottom plate portion 21 a of the recess 21 is provided with a plurality of circular sieves 23 having a diameter of 10 mm or a square of 10 mm × 10 mm penetrating in the thickness direction. As shown in FIG. 4, the base bottom plate 2 and the gantry 3 are positioned at predetermined positions by abutting the outer peripheral surface of the base bottom plate 2 against the abutting portion 31. Although not shown, the sleeve 1 and the base bottom plate 2 are fixed to the gantry 3 by fixing means such as screws.

Further, when the pressing load of the piston body 4 is 10 kN or more and 100 kN or less, the sieve 23 of the base bottom plate 2 has an opening area of each sieve 23 formed on the base bottom plate 2 with respect to the opening area A of the sleeve 1. It is desirable to form so that the aperture ratio (B / A) of the total area B combined is 0.20 or more and 0.70 or less.
When the opening ratio (B / A) is 0.20 or less, the pressing load of the piston body 4 is insufficient, and it becomes difficult to extrude the soil sample from the sieve 23 and prepare it. On the other hand, when the opening ratio (B / A) exceeds 0.70, the interval between the sieves 23 formed on the base bottom plate 2 is close and the strength of the base bottom plate 2 itself is reduced. It is prone to deformation and makes accurate preparation difficult.

  The base bottom plate 2 of the present embodiment is specifically formed of a highly rigid steel plate or stainless steel plate, and a Cr—Mo plating process having wear resistance is applied to the surface thereof. Further, the depth of the screen 23 of the base bottom plate 2 of the present embodiment, that is, the plate thickness t of the bottom plate portion 21 a of the recess 21 is 9 to 15 mm.

  Although not shown, the gantry 3 is provided with an opening for exposing the inner peripheral portion of the base bottom plate 2 downward in a state where the flange portion 22 of the base bottom plate 2 is placed on the gantry 3. ing. Therefore, when the flange portion 22 of the base bottom plate 2 is placed on the mount 3, the plurality of sieves 23 provided on the base bottom plate 2 are not blocked by the mount 3, and the exposed state is maintained. It has become so.

The piston body 4 is constituted by a hydraulic cylinder or the like, and is provided so as to be movable up and down in the axial direction of the sleeve 1. As shown in FIG. 3, the soil sample 9 a put into the sleeve 1 is used as the piston body 4. It can be pressed in the axial direction (vertical direction) of the sleeve 1 through a pressurizing portion 41 provided in the lower portion.
Although not shown in the figure, the soil sample preparation device 100 is provided with a vibration means for vibrating the piston body 4 in the axial direction of the sleeve 1, and while pressing the soil sample 9 a by the piston body 4, the frequency is reduced. Is 50 to 1000 Hz and a micro-vibration with an amplitude of 0.1 to 1.0 mm can be applied.

  As shown in FIGS. 2 and 3, the guide member 5 is provided so as to be able to engage with the outer peripheral portion of the pressurizing portion 41 of the piston body 4, and engages with the outer peripheral portion of the pressurizing portion 41. It has a shape having a portion 51 and a pair of connecting plate portions 52 erected on the surface of the cylindrical portion 51 in the radial direction. And the guide member 5 is attached to the raising / lowering means 8 such as a hydraulic cylinder via the connecting plate portion 52, and from this raising / lowering means 8, the connecting position connected to the upper portion of the sleeve 1 shown in FIG. It is supported so as to be movable up and down between a retracted position separated from the upper portion of the sleeve 1 shown. The guide member 5 is moved rectilinearly along the axial direction of the sleeve 1 by being guided along the guide shaft 81.

  Further, the overall length of the cylindrical portion 51 of the guide member 5 is formed longer than the distance between the connection position and the retracted position, and the guide member 5 is disposed at any position between the connection position and the retracted position. Also, the state in which the pressing portion 41 of the piston body 4 is inserted into the inside of the cylindrical portion 51 is maintained. In the state where the guide member 5 is disposed at the connecting position with the sleeve 1, the piston member 4 and the sleeve 1 are in communication with each other as shown in FIG. The internal movement is guided by the guide member 5.

In addition, when cleaning or exchanging each component constituting the soil sample preparation device 100, the pressure member 41 of the piston body 4 is extracted from the inside of the guide member 5 to pressurize the guide member 5 and the piston body 4. The unit 41 can be disassembled. The inner peripheral surface of the guide member 5 is, as shown in FIG. 2 and FIG. 3, provided with a diameter on the upper side larger than that on the lower side, and further on the connecting portion 53 between the upper side and the lower side. A slope is provided to gradually reduce the diameter from the upper side to the lower side. The inner peripheral surface on the lower side of the guide member 5 is provided with the same diameter as the inner peripheral surface of the sleeve 1.
Thus, since the diameter on the upper side of the inner peripheral surface of the guide member 5 is formed large, when the guide member 5 and the piston body 4 are assembled, the piston body 4 is easily placed inside the guide member 5. The pressurizing unit 41 can be incorporated. Further, since the connecting portion 53 between the upper side and the lower side of the inner peripheral surface of the guide member 5 is provided with a gradient that gradually decreases in diameter from the upper side to the lower side, the pressurizing portion 41 of the piston body 4 is provided. The guide can be smoothly guided from the upper side to the lower side of the guide member 5.

  Further, the soil sample preparation device 100 has a lock that allows the pressure member 41 to be inserted into the sleeve 1 by moving the piston body 4 downward in a state where the guide member 5 is disposed at the connection position shown in FIG. Means are provided. That is, the piston body 4 is provided so as to be able to press the soil sample 9a inside the sleeve 1 in a state where the guide member 5 is disposed at the connection position. The locking means may be electrical means for controlling the movement of the piston body 4 or mechanical restraint means. Specifically, the soil sample preparation device 100 is provided with a position sensor (not shown) for detecting the position of the lifting / lowering means 8, and the state in which the lifting / lowering means 8 is disposed at the lowered position, that is, the guide member 5 is sleeved. The piston body 4 is controlled so as to be able to move downward only when the position sensor detects the state of being disposed at the connection position with 1. For this reason, when it can not be detected that the guide member 5 is disposed at the connection position, the piston body 4 can not be moved downward. In this way, the piston body 5 can be moved downward only when the guide member 5, the sleeve 1 and the base bottom plate 2 are held at predetermined positions, so that the piston body 4 can be moved from the guide member 5 to the inside of the sleeve 1. It can be inserted smoothly and the preparation can be done safely.

  Further, the lower surface of the piston body 4 is provided so as to maintain an interval of 20 mm or more between the upper surface of the base bottom plate 2 and avoids contact between the piston body 4 and the base bottom plate 2, and the piston body 4 and the base It is intended to prevent damage to the base bottom plate 2 and the piston body 4 due to the foreign matter being caught between the bottom plate 2 and the like.

  The receiving portion 6 is disposed below the base bottom plate 2, and the soil sample 8 b prepared by being pushed out from the sieve 23 of the base bottom plate 2 can be stored on the receiving portion 6. The soil samples 8b placed on the receiving portion 6 can be collected together. In the soil sample preparation device 100 of the present embodiment, the receiving portion 6 is provided so as to be movable up and down by a screw-type jack 61, and the interval between the receiving portion 6 and the base bottom plate 2 is adjusted. Can do.

Next, a procedure for preparing a soil sample from the soil sample 9a using the above-described soil sample preparation device 100 will be described.
First, as shown in FIG. 2, the guide member 5 is disposed at a retracted position separated from the upper portion of the sleeve 1, and the soil sample 9 a is put into the sleeve 1 from the gap between the sleeve 1 and the guide member 5. . Next, the guide member 5 is moved downward from the retracted position to the connection position with the sleeve 1 by the lifting means 8, and the upper portion of the sleeve 1 and the lower portion of the guide member 5 are engaged and connected. In this state, the pressurizing portion 41 of the piston body 4 is in a state of being engaged with the inner peripheral surface of the guide member 5 on the upper side of the guide member 5.

  Next, as shown in FIG. 3, the pressurizing portion 41 of the piston body 4 is moved down from the inside of the guide member 5 to the inside of the sleeve 1, and the soil sample is placed between the pressurizing portion 41 and the base bottom plate 2. Press 9a. The soil sample 9 a pressed by the pressing unit 41 is pushed out of the sieve 23 by being pressed against the base bottom plate 2, and the soil sample 9 b having passed through the sieve 23 is accumulated on the receiving unit 6. On the other hand, foreign matter or the like having a large particle diameter which can not pass through the sieve 23 is left inside the sleeve 1 and automatically separated from the soil sample 9b.

Thus, in the soil sample preparation apparatus 100, the soil sample 9a is put into the sleeve 1 and is sandwiched between the base bottom plate 2 and the piston body 4 (pressurizing portion 41) to screen the base bottom plate 2. By passing through the eyes 23, it is possible to produce the soil sample 9b having a particle diameter adjusted to pass through the sieve 23 having a diameter of 10 mm. In addition, since the base bottom plate 2 provided with the sieve 23 is made of a high rigidity steel material, a higher pressing force is applied compared to the case where the soil sample 9a is manually pressed against the sieve 23 The soil sample 9a can be pushed out from the sieve mesh 23, and the soil sample 9b can be prepared in a short time. Furthermore, by setting it as the base bottom plate 2 made of steel, the opening of the sieve 23 can be prevented, and the accuracy of the compounding test of the soil sample 9b can be secured. Further, since the sleeve 1 and the base bottom plate 2 are separately formed, replacement of the base bottom plate 2 is easy, and cleaning of the sleeve 1 and the base bottom plate 2 can be easily performed.
And by using the soil sample preparation device 100 configured in this way, the preparation work of the soil sample 9b can be automated, so the opportunity for the operator to directly touch the soil sample 9a is reduced, and safety and hygiene are achieved. Both sides can be maintained.

  When preparing the soil sample 9b from a soil sample 9a having a relatively low viscosity such as sandy soil or black spots, when pressed as it is, the soil sample 9a is block-shaped between the base bottom plate 2 and the piston body 4 It is easy to cause clogging of the screen 23. However, in the soil sample preparation device 100 of the present embodiment, the histone body 4 can be vibrated in the axial direction of the sleeve 1 by the vibration means, and therefore, the piston body 4 applies a slight vibration while pressing the soil sample 9a. The soil sample 9a can be smoothly passed through the sieve 23 while preventing the soil sample 9a from being compacted.

  In the soil sample preparation device 100, a guide member 5 that can be engaged with the outer peripheral portion of the piston body 4 (pressurizing portion 41) is provided, and the piston member 4 and the sleeve 1 are communicated with each other by the guide member 5. Therefore, the movement of the piston body 4 into the sleeve 1 is guided by the guide member 5, and the piston body 4 can be smoothly inserted into the sleeve 1 to press the soil sample 9a. Further, in a state where the guide member 5 is disposed at a position where the guide member 5 is connected to the sleeve 1, the sleeve 1 is kept pressed by the guide member 5, so that the sleeve 1 and the base bottom plate 2 are prevented from being lifted. As described above, the guide member 5, the sleeve 1, and the base bottom plate 2 are held in a predetermined position by allowing the piston body 4 to be pressed only in a state where the guide member 5 is disposed at the connection position with the sleeve 1. As long as the piston body 4 can be smoothly inserted from the guide member 5 into the inside of the sleeve 1, the preparation operation can be performed safely.

In the example shown in FIGS. 2 and 3, the screen 23 of the base bottom plate 2 is formed by a straight hole. However, like the base bottom plate 20 shown in FIG. 5, the screen 23 has an opening on the sleeve 1 side. Alternatively, an R chamfer 24 having a radius of 1 mm or more and 5 mm or less may be formed.
By forming an R chamfer 24 having a radius of 1 mm or more and 5 mm or less in the opening of the sieve 23 on the sleeve 1 side, the soil sample 9a can be smoothly flowed from the inside of the sleeve 1 to the inside of the sieve 23, The preparation time can be shortened. In the base bottom plate 20 of FIG. 5, the same reference numerals are given to common elements with the base bottom plate 2, and description thereof is omitted.

  Further, in the soil sample preparation device 100 of the above embodiment, the lower surface of the piston body 4 is provided so as to maintain a distance of 20 mm or more between the upper surface of the base bottom plate 2 and the piston body 4 and the base bottom plate 2. In addition to avoiding contact and preventing damage to the base bottom plate 2 and the piston body 4 due to foreign matter etc. being pinched between the piston body 4 and the base bottom plate 2, a pressure sensor is provided on the piston body 4 By feeding back the change in the pressing force, the contact between the piston body 4 and the base bottom plate 2 or the damage of the base bottom plate 2 and the piston body 4 caused by foreign matter or the like may be prevented.

Next, in order to confirm the effects of the present invention, soil samples were prepared from a plurality of soil samples.
(Difference due to pressure)
First, a 4 kg soil sample preparation operation required for one cement-based solid material blending test is performed using the soil sample preparation apparatus 100 of the present embodiment shown in FIGS. 1 to 4 (this method). The method was carried out with each of the conventional manual sieving methods (conventional methods), and the time required for the preparation of soil samples by each method was compared. In the present method, the pressure applied by the piston body was set to 80 kN. Further, in the present method and the conventional method, the base bottom plate has a circular sieve having a diameter of 10 mm, and an opening having a total area B obtained by combining the opening area of the sieve formed on the base bottom plate with respect to the opening area A of the sleeve. A ratio (B / A) of 0.50 was used. The results are shown in Table 1.

  As can be seen from Table 1, by using the soil sample preparation apparatus of the present embodiment, the time required for viscous soil and loam can be reduced to about 1/5 compared to the case of manual work, and the silt and sandy viscosity is reduced. In soil, the time required was reduced to about 1/4.

(Difference by opening ratio of sieve)
In the soil sample preparation apparatus 100 of the present embodiment shown in FIG. 1 to FIG. 4, a 4 kg soil sample preparation operation was performed using a base bottom plate with each sieve opening ratio (B / A) changed. The time required for the preparation of soil samples by each base bottom plate was compared. The pressure applied by the piston was set to 80 kN, and viscous soil was used as the soil sample. Table 2 shows the results.

  In the base bottom plate having an opening ratio (B / A) of 0.15, the pressure increased due to consolidation, and it was not possible to prepare a soil sample. In the base bottom plate which makes an opening ratio (B / A) 0.20 or more and 0.70 or less, the preparation operation could be performed well. On the other hand, with the base bottom plate with an opening ratio (B / A) of 0.80, the time required for preparation could be shortened, but after repeated use 10 times, the base bottom plate and sieve were deformed and continued use. Is no longer possible.

(A difference due to the presence or absence of R chamfer on sieve)
In the soil sample preparation apparatus 100 of the present embodiment shown in FIGS. 1 to 4, Table 3 has an arbitrary size in the upper opening (opening on the sleeve side) and the lower opening (opening on the receiving part side). Preparation work of 4 kg of soil samples was performed using the base bottom plate which formed R chamfering of this, and comparison of the time required for preparation of the soil sample by each base bottom plate was performed. The pressure applied by the piston was set to 90 kN, and viscous soil was used as the soil sample. Further, the thickness t of the bottom plate portion of the base bottom plate was 11 mm, and the opening ratio (B / A) of the sieve was 0.50. Table 3 shows the results.

  As can be seen from Table 3, when the R-chamfered with a radius of 1 mm or more and 5 mm or less is attached to the upper opening of the sieve, ie the opening on the sleeve side, the bite of the soil sample is improved and the required time for preparation can be shortened . In addition, when R chamfering with a radius of 3 mm was provided in both the upper opening and the lower opening of the sieve mesh, adhesion of the soil sample to the inside of the sieve mesh was greatly reduced, and cleaning became easy.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Sleeve 2,20 Base base plate 3 Base 4 Piston body 5 Guide member 6 Receiving part 7 Operation part 8 Elevating means 9a Soil sample 9b Soil sample 21 Recess 21a Bottom plate part 22 Flange part 23 Sieve 24 R chamfer 31 Abutting part 41 Addition Pressure part 51 Cylindrical part 52 Connection plate part 53 Connection part 61 Jack 81 Guide shaft 100 Soil sample preparation device

Claims (6)

With a cylindrical sleeve,
A steel base bottom plate attached to the bottom side opening of the sleeve;
A piston body that can be inserted into the sleeve and that can be pressed in the axial direction of the sleeve,
The base bottom plate is provided with a plurality of sieves having a diameter of 10 mm or a square of 10 mm × 10 mm,
A soil sample preparation characterized in that a receiving part is provided below the base bottom plate for collecting a soil sample prepared by pushing out the soil sample put into the sleeve from the sieve mesh. apparatus.   The soil sample preparation apparatus according to claim 1, further comprising a vibrating unit configured to vibrate the piston body in the axial direction of the sleeve. When the pressing load of the piston body is 10 kN or more and 100 kN or less,
The opening ratio (B / A) of the total area B, which is the total opening area of the sieve screens formed on the base bottom plate with respect to the opening area A of the sleeve, is 0.20 or more and 0.70 or less. The soil sample preparation apparatus according to claim 1 or 2.   The soil sample preparation device according to any one of claims 1 to 3, wherein an R chamfer having a radius of 1 mm or more and 5 mm or less is formed in an opening on the sleeve side of the sieve. A cylindrical guide member provided to be engageable with the outer peripheral portion of the piston body;
Raising and lowering means for supporting the guide member so as to be movable up and down between a connected position connected to the upper portion of the sleeve and a retracted position spaced from the upper portion of the sleeve;
The soil material according to any one of claims 1 to 4, further comprising: locking means for enabling the piston body to be inserted into the inside of the sleeve when the guide member is disposed in the connection position. Sample preparation device. Under surface of the piston body, soil sample preparation according to any one of claims 1 5, characterized in that it is provided to maintain a minimum of 20mm between the upper surface of the base bottom plate apparatus.

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